Safety chain for door knobs



A ril 11, 1967 R. E. SIPES SAFETY CHAIN FOR DOOR KNOBS Filed Feb. 1, 1965 2 Sheets-Sheet 1 I NVEN TOR Robe/v E Sipes Filed Feb. 1, 1965 April 11, 1967 R. E. SIPES 3,313,566

SAFETY CHAIN FOR DOOR KNOBS 2 Sheets-Sheet 2 INVENTOR. Qoben E. S/pc's BY uman 7AM United States Patent This invention relates to improvements in locking devices and more particularly, but not by way of limitation, to a safety chain locking device for use in combination with a door keeper plate and a door knob for permitting only limited opening of the door and deterring entry of unwanted persons through the doorway.

There are many instances wherein it is desirable to open a door only a relatively small amount such as in order to receive a delivery through the opening, or to enable visual observance of the area on the opposite side of the door, but at the same time prevent a complete opening of the door in order to deter the entry of an undesirable or unwanted person through the open doorway. The usual night chain or guard latch in widespread use today for permitting a limited opening of a door in this manner normally includes a pair of chain holding elements wherein one of the elements is secured to the door and the other of the elements is secured to the door jamb whereby a chain may be extended therebetween or from the door to the door jamb to limit or restrict the opening of the door. These devices have certain disadvantages, however, in that the installation thereof is substantially permanent since the elements of the device are usually screwed or otherwise secured to the door and door jamb. This renders use of the device on other door openings difiicult since the entire device must be unscrewed from the supporting structure and re-installed by screwing or nailing thereof to the other door structure. This obviously is undesirable since the door and door jamb will be marred by the screw holes remaining subsequent to removal of the device. In addition, it is difiicult to replace the device in the same position since the screws may not hold when replaced in the same holes. Furthermore, it has been found that a considerable force against the door and chain can dislodge one of the elements and release the door for full opening thus rendering the device unable to function for limiting the opening of the door.

The present invention contemplates a safety chain device for use with the keeper plate and door knob in a manner substantially precluding accidental dislodging of the device when in use. In addition, the novel safety chain device is particularly designed and constructed for ease of installation on or removal from substantially any door knob and keeper plate in association therewith without any damage or marring of the door or keeper plate. Thus, one of the devices may be easily carried about on the person for use with substantially any door, either an outside door or an inside door, as desired. For example, a travelling person may carry one or more of the devices at all times for use with doors in a motel, or the like, or a person engaged in baby sitting may carry one of the devices for use on the doors of homes wherein he or she may be employed.

It is an important object of this invention to provide a safety chain locking device for use in combination with substantially any door and keeper plate in association therewith.

It is another object of this invention to provide a novel safety chain latch for doors particularly designed and constructed for substantially eliminating dislodging thereof while in use, thus providing an efficient operation.

Another object of this invention is to provide a novel safety chain latch for doorknobs which may be utilized with substantially any door in a manner substantially precluding damage or marring of the door.

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A further object of this invention is to provide a novel safety chain latch for doors which may be quickly and easily installed for use and may be readily removed for transport to another location.

A still further object of this invention is to provide a novel safety chain latch for doors that is simple and eflicient in operation and economical and durable in construction.

Other and further objects and advantageous features of the present invention will hereinafter more fully appear in connection with a detailed description of the drawings in which:

FIGURE 1 is a perspective view of a safety chain latch embodying the invention with portions thereof depicted in dotted lines for purposes of illustration.

FIGURE 2 is a front elevational view of a safety chain latch device embodying the invention and disposed within the door keeper plate of a door frame or door jamb.

FIGURE 3 is a front elevational view of a safety chain latch embodying the invention depicted in use in combination with a closed door.

FIGURE 4 is an elevational view of a modified embodiment of the invention with portions thereof depicted in dotted lines for purposes of illustration.

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 4.

Referring to the drawings in detail, reference character 10 generally indicates a safety chain latching device comprising a rod or shaft 12 having a pair of radially outwardly extending arms 14 and 16 journalled thereon in any well known manner. A suitable spring 18 is disposed around the shaft 12 and interposed between the arms 14 and 16 for constantly urging the arms in a direction away from each other for a purpose as will be hereinafter set forth. Stop members 20 and 22 are provided on the opposite ends of the shaft 12 and disposed outwardly with respect to the arms 14 and 16 for retaining the arms in position on the shaft 12.

Whereas the arms 14 and 16 may be of any suitable configuration, it is preferable that the arms be of an angular or substantially L-shaped as shown in the drawings with the portions 15 and 17 thereof respectively, extending outwardly from the shaft 12 being substantially flat and with the outer extremities thereof bent or otherwise formed at substantially right angles thereto to provide engaging fingers 24 and 26 for the arms 14 and 16, respectively. It is preferable that the outer side edge of the fingers 24 and 26 be serrated, jagged or provided with teeth as shown at 28 in FIGURE 1.

A chain 32 of any suitable link type is carried by the shaft 12 and is preferably secured thereto in such a manner that the opposite ends 34 and 36 of the chain 32 are journalled around the shaft and interposed between the arm members 14 and 16 and the respective stop members 20 and 22. Thus, the ends 34 and 36 of the chain 32 are maintained in spaced relationship and adjacent the stop members 26 and 22 by the action of the spring 18 acting on the arms 14 and 16. The chain is of a suitable length to permit positioning thereof around a door knob 38 with ease and for a purpose as will be hereinafter set forth. The effective length of the chain may be shortened in any suitable manner, such as by the use of an S-link 40 (FIGURE 2) in a manner as will be hereinafter set forth.

The door knob 38 depicted herein is merely illustrative and may be of substantially any well known type normally provided on a door 46 for actuation of the usual door latch members (not shown). A suitable keeper plate 42 is usually secured to the door jamb or facing 44 by a plurality of screws 43 and is normally provided with an aperture 48 disposed in substantial alignment with a complementary recess provided in the door jamb 44 for re- 3 ceiving the door latch member therein when the door 46 is in a closed position.

The chain latch device is utilized in combination with the keeper plate 42 and door knob 38 as particularly shown in FIGURES 2 and 3. In order to secure the chain latch 10 to the keeper plate 42, the arms 14 and 16 may be manually moved in a direction toward each other and against the action of the spring 18 whereby the gripping fingers 24 and 26 are brought sufficiently close together for insertion thereof through the aperture 48 and within the recess provided in the door jamb 44 in association with the keeper plate 42. When the fingers 24 and 26 are disposed within the recess, the manual pressure on the arms 14 and 16 may be released. The spring 18 acting outwardly against the arms 14 and 16 urges the arms in opposite directions or away from each other whereby the serrated edges '28 of the fingers 24 and 26 bite into the wall of the recess 48 for securely retaining the fingers 24 and 26 in position therein.

With the fingers 24 and 26 engaged within the recess 48, the portions and 17 of the arms 14 and 16 will be disposed substantially flat against the edge surface of the door jamb or facing 44 thus precluding interference with the normal operation of the door latch member with respect to the keeper plate and recess. The shaft 12 and stop members and 22 as well as the chain 32 will be disposed outwardly or slightly away from both the side and front edges of the door jamb 44 and, thus, the chain latch device 10 in no manner interferes with the normal opening and closing of the door 46.

When the door 46 is in a closed position, as shown in FIGURE 3, the chain 32 may be readily looped 'or disposed around the door knob handle as clearly shown in FIGURE 3 whereby opening of the door 46 will be restricted. In the event the length of the chain 32 permits a further opening of the door than is desired, the effective length of the chain 32 may be shortened by use of the link members of the chain. Whereas the shortening of the chain as depicted in FIGURE 3 shows the lower portion of the chain fastened to the upper portion of the chain, it is to be noted that the chain may be shortened by connecting substantially any pair of link members by use of the S-hook 40.

As long as the chain latch device 10 is connected to the keeper plate 42 as hereinbefore set forth and the chain is disposed around the door knob 38, the door 46 can not be opened through a sufiicient distance for permitting entry of unwanted persons therethrough. Furthermore, the door 46 can not be opened a sufiicient distance to permit tampering with the arms 14 and 16 for removal thereof from connection with the keeper plate 42. In addition, the arms 14 and 16 are preferably constructed of a metal whereby the strength of the arms 14 and 16 in combination with the strength of the chain 32 substantially precludes dislodging or breaking of any of the elements by exerting extreme force on the door and against the chain.

When it is desired to remove the chain latch device 10, the manual pressure may again be exerted on the arms 14 and 16 for moving the arms in a direction toward each other and against the action of the spring 18 for releasing the biting engagement of the gripping fingers 24 and 26 with the recess 48. Of course, this can only be done when the door is in an open position sufficiently removed from the door jamb for permitting access to the arms 14 and 16 and aperture 48.

Referring now to FIGURES 4 and 5, a modified chain latch device generally indicated at 50 is depicted therein. The device 50 is substantially similar to the device 10 and comprises a rod or shank 52 having stop members 54 and 56 suitably secured at the opposite ends thereof for retaining arm members 58 and 60 on the shaft 52. The arms 58 and 60 are journalled around the shaft in any suitable manner (not shown) and comprise a substantially straight or fiat portion 62 and 64, respectively, which extend radially outwardly from the shaft 52 and each of which terminates in a gripping finger 66 only one of which is shown in the drawings. The gripping fingers 66 are preferably disposed at substantially right angles with respect to the respective fiat members 62 and 64 whereby the flat portions 62 and 64 will be disposed adjacent the door facing when the gripping fingers 66 are connected with the keeper plate as hereinbefore set forth in the preferred embodiment.

A substantially U-shaped connecting member 68 is journalled on the shaft 52 in such a manner that the open or spaced ends thereof span the arm 60 as clearly shown in FIGURE 4 and a similar U-shaped connecting member 70 is journalled on the shaft 52 whereby the spaced ends thereof span the arm 58. A chain 72 is secured between the U-shaped members 68 and 70. In addition, a hook member 74 is journalled on the shaft 52 and as shown herein is preferably disposed in the proximity of one of the U-shaped members 68, but not limited thereto. A spring 76 is disposed around the shaft 52 and bears against the U-shaped member 70 and the hook member 74 for constantly urging the arms 58 and 60 in a direction away from each other.

In use, the chain latch device 50 is connected with the keeper plate 42 by securing the arms 58 and 60 to the recess provided in the door jamb 44 in the same manner as hereinbefore set forth in the preferred embodiment. The chain 72 may then be looped or disposed around the handle of the door knob 38 for limiting the opening movement of the door 46. When it is desired to shorten the effective length of the chain 72, one of the links of the chain such as the link 78 may be brought into engagement with the hook 74 as shown particularly in detail in FIG- URE 5. As long as the latch device 50 is connected with the keeper plate 62, the opening of the door 46 will be limited and in no manner can a door he opened sufiiciently for any tampering or dislodging of the arms 58 and 60 from the connection with the keeper plate. It will be further apparent that the door can in no manner he opened a sufiicient distance for disengaging the chain from its position around the door knob handle.

From the foregoing, it will be apparent that the present invention provides a novel chain latch device which may be quickly and easily installed on substantially any door keeper plate and readily removed therefrom with no marring or damage to the keeper plate or associated door structure. The novel latch device is particularly designed and constructed for substantially eliminating accidental dislodging or tampering thereof from the installed position during utilization thus increasing the safety of controlling the limited opening of a door. The novel device is simple and efiicient in operation and economical and durable in construction. I

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims, without departing from the spirit of the invention.

What is claimed is:

1. In combination with a door having a door knob and a door jamb in association therewith having a latch receiving recess, a chain latch device comprising a plurality of spaced gripping members, spring means cooperating with the gripping members for urging the gripping members apart into engagement with the side walls of the recess, and chain means connected to said members for disposition around the door knob in order to limit the opening of the door.

2. In combination with a door having a door knob and a door jamb in association therewith having a latch receiving recess, a chain latch device comprising gripping means, spring means for yieldably urging the gripping means with the opposite side walls of the recess, chain means connected to said gripping means for disposition around the door knob in order to limit the opening of the door, and means for shortening the eflective length of the chain means.

3. In combination with a door having a door knob and a door jamb in association therewith having a latch receiving recess, a chain latch device comprising a rod member, gripping members carried by the rod, spring means carried by the rod member for urging the gripping members into engagement with opposed side walls of the recess, stop means provided on the rod for retaining the spring urged gripping members thereon, and chain means carried by the rod and engageable with the door knob in order to limit the opening of the door.

4. In combination with a door having a door knob and a door jamb in association therewith having a latch receiving recess, a chain latch device comprising a rod member, a pair of spaced gripping members carried by the rod, spring means carried by the rod member for urging the gripping members into engagement with opposed side walls of the recess, stop means provided on the rod for retaining the spring urged gripping members thereon, chain means carried by the rod and engageable with the door knob in order to limit the opening of the door, and means for shortening the efiective length of the chain means.

5. In combination with a door having a door knob and a door jamb having a latch receiving recess and keeper plate therefor, a chain latch device comprising a rod member, a pair of spaced arm members journalled on the rod and longitudinally movable therealong, spring means interposed between the arm members for constantly urging the arm members in a direction away from each other, stop means carried by the. rod for retaining the arms in position thereon, gripping means provided on each arm member for engaging the side walls of the recess whereby the arm members are disposed against the keeper plate, and chain means carried by the rod for engagement with the door knob to limit the opening of the door.

6. In combination with a door having a door knob and a door jamb having a latch receiving recess and keeper plate therefor, a chain latch device comprising a rod member, a pair of arm members journalled on the shaft for rotation therearound and longitudinally movable ther along, spring means disposed around the rod and interposed between the arms for constantly urging the arms in a direction away from each other, stop means provided on the opposed ends of the rod for retaining the arm members thereon, each of said arm members comprising a substantially fiat portion extending radially outwardly from the rod and a gripping member at the outer end thereof extending substantially at right angles with respect to the flat portion for engaging the side walls of the recess whereby the flat portions are disposed adjacent the keeper plate, and chain means carried by the rod for disposition around the door knob in order to limit the opening of the door.

7. In combination with a door having a door knob and a door jamb having a latch receiving recess and keeper plate therefor, a chain latch device as set forth in claim 6 and including hook means for shortening the effective length of the chain means.

References Cited by the Examiner UNITED STATES PATENTS 553,496 1/ 1896 Caminetti 292-295 572,046 11/1896 Bailey 292-288 2, 199,3 69 4/ 1940 Bernstein 292-28 8 2,288,022 6/1942 OBrien et al. 292-291 2,924,479 2/ 1960 Butler 292-296 EDWARD C. ALLEN, Primary Examiner. RICHARD E. MOORE, Examiner. 

1. IN COMBINATION WITH A DOOR HAVING A DOOR KNOB AND A DOOR JAMB IN ASSOCIATION THEREWITH HAVING A LATCH RECEIVING RECESS, A CHAIN LATCH DEVICE COMPRISING A PLURALITY OF SPACED GRIPPING MEMBERS,, SPRING MEANS COOPERATING WITH THE GRIPPING MEMBERS FOR URGING THE GRIPPING MEMBERS APART INTO ENGAGEMENT WITH THE SIDE WALLS OF THE RECESS, AND CHAIN MEANS CONNECTED TO SAID MEMBERS FOR DISPOSITION AROUND THE DOOR KNOB IN ORDER TO LIMIT THE OPENING OF THE DOOR. 